The invention relates generally to the field of non-invasive imaging and more specifically to the use of multi-energy tomosynthesis imaging.
In modern healthcare facilities, imaging systems may be used in the treatment of patients, such as in the in the identification and diagnosis of diseases or other conditions. For example, X-ray based systems, such as radiographic systems, computed tomography (CT) systems, dual-energy systems, and tomosynthesis, create internal images or views of a patient based on attenuation of X-rays passing through the patient, i.e., different tissues absorb or reflect X-rays differently. Conversely, other imaging modalities, such as ultrasound, magnetic resonance imaging (MRI), and positron emission tomography (PET), may rely on other physical phenomena to create internal images or views of the patient in a non-invasive manner.
As noted above, tomosynthesis is one example of an X-ray based technique for generating internal views of the patient. In a tomosynthesis system, the X-rays are emitted at different positions relative to the patient so that three-dimensional, or depth, information is available in the acquired images. In this manner, three-dimensional images of the patient's internal regions may be obtained. However, while tomosynthesis techniques are effective in reconstructing three-dimensional images of the patient's internal regions, simultaneous presence of bone and soft tissue (or other tissue types) in the images may limit their usefulness if diagnostically interesting regions are masked or hidden by opaque tissue.
One technique used to improve the visibility of masked tissue in X-ray based imaging utilizes X-ray emissions having different energy spectra or profiles. For example, X-ray images may be acquired of a patient or portion of a patient using two different X-ray energy profiles (i.e., dual energy), such that a different set of image data is acquired for each energy profile. The different sets of image data, when processed, may be used to construct different images that characterize the density or attenuating characteristics of the imaged volume. By decomposing the acquired image data, images may also be generated which differentially reflect the composition of the imaged volume, such as bone or soft tissue in a medical context.
However, tomosynthesis imaging utilizing such dual or multi-energy techniques may still have shortcomings that reduce its usefulness. For example, a tomosynthesis image acquired using dual energy X-ray imaging may be difficult to interpret since anatomic structures, such as skeletal structures, may be removed which are useful in providing context to a reviewing radiologist. Alternatively, the image quality may be reduced by patient motion, such as respiration or cardiac motion, which may introduce motion-related artifacts into the images. The present technique may address these problems as well as others.